Abstract As the second carbon storage pool, soil is easily influenced by human activities. Mulched drip irrigation is a water-saving irrigation technique used widely in arid and semi-arid regions. However, information about the response of CO2 exchange to mulched drip irrigation, such as the wetter and warmer soil, is limited. To identify the carbon emissions effects of mulched drip irrigation, we carried out a field experiment using drip irrigation with and without clear plastic mulching during the cotton growing seasons of 2015 and 2016. We monitored the temporal and spatial variation of soil moisture, soil temperature, cotton growth stage, biomass, lint yield, CO2 emissions, and the relationship between soil respiration rate and soil climate. The results showed that plastic mulching drip irrigation increased soil moisture and soil temperature, especially during the early and middle growth stages of cotton. The soil respiration rate was related positively to the higher soil temperature and moisture conditions promoted by plastic film mulching, although the coefficients of determination were low (R2 were 0.480 and 0.205, corresponding p-value was both 0.000, respectively). The highest value of soil respiration was obtained within the narrow rows under the drip tape, regardless of the practice of mulching or not. The soil respiration rate under plastic mulch in the narrow and wide rows were on average 28.35 % and 22.48 % higher than non-mulched control. Meanwhile, the amount of total CO2 emissions was significantly increased by 25.34 % and 28.90 % in these same rows, respectively (p-values were 0.006 at narrow rows and 0.010 at wide rows in the first year, and 0.000 at same rows in the second year). The differences of CO2 emission in the bare soil was not significant between mulched plots and non-mulched control (p-values were 0.757 and 0.918 in the first and second growing seasons, respectively). In addition, plastic mulching significantly improved the biomass and yield of cotton, by 61.49 % and 12.83 % on average (p-values were 0.034 and 0.039 in 2015, 0.024 and 0.032 in 2016), respectively. The results indicate that the application of drip irrigation under plastic mulch could increase soil water content and temperature, promote cotton growth, and improve lint yield. However, it may also lead to increased CO2 emissions, which can intensify the warming of the climate.

中文翻译：

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膜下滴灌棉田碳排放特征

摘要 土壤作为第二个碳储库，极易受到人类活动的影响。地膜滴灌是一种广泛应用于干旱半干旱地区的节水灌溉技术。然而，关于 CO2 交换对覆盖滴灌（如较湿和较温暖的土壤）的响应的信息是有限的。为了确定覆盖滴灌的碳排放影响，我们在 2015 年和 2016 年棉花生长季节使用滴灌和不覆盖地膜进行了田间试验。我们监测了土壤水分、土壤温度、棉花生长阶段、生物量、皮棉产量、CO2 排放以及土壤呼吸速率与土壤气候之间的关系。结果表明，覆膜滴灌增加了土壤水分和土壤温度，特别是在棉花的早期和中期生长阶段。土壤呼吸速率与地膜覆盖促进的较高土壤温度和水分条件呈正相关，尽管决定系数较低（R2 分别为 0.480 和 0.205，相应的 p 值分别为 0.000）。土壤呼吸的最高值是在滴灌带下的窄行内获得的，无论是否进行覆盖。窄行和宽行地膜覆盖下土壤呼吸率平均比未覆盖控制高28.35%和22.48%。同时，这些相同行的 CO2 排放总量分别显着增加了 25.34% 和 28.90%（第一年的 p 值为窄行 0.006 和宽行 0.010，0. 000 在第二年的同一行）。覆盖地块和未覆盖地块之间裸土中 CO2 排放的差异不显着（第一个和第二个生长季节的 p 值分别为 0.757 和 0.918）。此外，地膜覆盖显着提高了棉花的生物量和产量，平均提高了 61.49% 和 12.83%（2015 年的 p 值分别为 0.034 和 0.039，2016 年分别为 0.024 和 0.032）。结果表明，地膜下滴灌可提高土壤含水量和温度，促进棉花生长，提高皮棉产量。然而，它也可能导致二氧化碳排放量增加，从而加剧气候变暖。覆盖地块和未覆盖地块之间裸土中 CO2 排放的差异不显着（第一个和第二个生长季节的 p 值分别为 0.757 和 0.918）。此外，地膜覆盖显着提高了棉花的生物量和产量，平均提高了 61.49% 和 12.83%（2015 年的 p 值分别为 0.034 和 0.039，2016 年分别为 0.024 和 0.032）。结果表明，地膜下滴灌可提高土壤含水量和温度，促进棉花生长，提高皮棉产量。然而，它也可能导致二氧化碳排放量增加，从而加剧气候变暖。覆盖地块和未覆盖地块之间裸土中 CO2 排放的差异不显着（第一个和第二个生长季节的 p 值分别为 0.757 和 0.918）。此外，地膜覆盖显着提高了棉花的生物量和产量，平均提高了 61.49% 和 12.83%（2015 年的 p 值分别为 0.034 和 0.039，2016 年分别为 0.024 和 0.032）。结果表明，地膜下滴灌可提高土壤含水量和温度，促进棉花生长，提高皮棉产量。然而，它也可能导致二氧化碳排放量增加，从而加剧气候变暖。平均为 83%（2015 年的 p 值分别为 0.034 和 0.039，2016 年分别为 0.024 和 0.032）。结果表明，地膜下滴灌可提高土壤含水量和温度，促进棉花生长，提高皮棉产量。然而，它也可能导致二氧化碳排放量增加，从而加剧气候变暖。平均为 83%（2015 年的 p 值分别为 0.034 和 0.039，2016 年分别为 0.024 和 0.032）。结果表明，地膜下滴灌可提高土壤含水量和温度，促进棉花生长，提高皮棉产量。然而，它也可能导致二氧化碳排放量增加，从而加剧气候变暖。